I cannot understand how a teacher (substitute, retired, permanent, purple or whatever) offering to pay a para a few bucks from her own pocket to help her provide the best learning experience for a classroom of children could possibly cause drama.
The para had two choices---take it or leave it. Why an adult would be discussing this private matter with friends/coworkers and finding it such a dilemma is really puzzling. She can do it, make a few bucks for the holidays, or not do it and tell the teacher "sorry but I cannot." It is nobody else's business. Not the principal, not the other staff.
Take it or leave it. Yes or no. That's it.